Effect of hypohydration on gastric emptying and intestinal absorption during exercise

A. J. Ryan, G. Patrick Lambert, X. Shi, R. T. Chang, R. W. Summers, C. V. Gisolfi

Research output: Contribution to journalArticle

55 Citations (Scopus)

Abstract

Dehydration and hyperthermia may impair gastric emptying (GE) during exercise; the effect of these alterations on intestinal water flux (WF) is unknown. Thus the purpose of this study was to determine the effect of hypohydration (~2.7% body weight) on GE and WF of a water placebo (WP) during cycling exercise (85 min, 65% maximal oxygen uptake) in a cool environment (22°C) and to also compare GE and WF of three carbohydrate- electrolyte solutions (CES) while the subjects were hypohydrated. GE and WF were determined simultaneously by a nasogastric tube placed in the gastric antrum and via a multilumen tube that spanned the duodenum and the first 25 cm of jejunum. Hypohydration was attained 12-16 h before experiments by low- intensity exercise in a hot (45°C), humid (relative humidity 50%) environment. Seven healthy subjects (age 26.7 ± 1.7 yr, maximal oxygen uptake 55.9 ± 8.2 ml · kg-1 · min-1) ingested either WP or a 6% (330 mosmol), 8% (400 mosmol), or a 9% (590 mosmol) CES the morning following hypohydration. For comparison, subjects ingested WP after a euhydration protocol. Solutions (~2.0 liters total) were ingested as a large bolus (4.6 ml/kg body wt) 5 min before exercise and as small serial feedings (2.3 ml/kg body wt) every 10 min of exercise. Average GE rates were not different among conditions (P > 0.05). Mean (±SE) values for WF were also similar (P > 0.05) for the euhydration (15.3 ± 1.7 ml · cm-1 · h-1) and hypohydration (18.3 ± 2.6 ml · cm-1 · h-1) experiments. During exercise after hypohydration, water absorption was greater (P < 0.05) with ingestion of WP (18.3 ± 2.6) and the 6% CES (16.5 ± 3.7), compared with the 8% CES (6.9 ± 1.5) and the 9% CES (1.8 ± 1.7). Mean values for final core temperature (38.6 ± 0.1°C), heart rate (152 ± 1 beats/min), and change in plasma volume (-5.7 ± 0.7%) were similar among experimental trials. We conclude that 1) hypohydration to ~3% body weight does not impair GE or fluid absorption during moderate exercise when ingesting WP, and 2) hyperosmolality (>400 mosmol) reduced WF in the proximal intestine.

Original languageEnglish (US)
Pages (from-to)1581-1588
Number of pages8
JournalJournal of Applied Physiology
Volume84
Issue number5
StatePublished - May 1 1998
Externally publishedYes

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Gastric Emptying
Intestinal Absorption
Exercise
Water
Placebos
Electrolytes
Carbohydrates
Gastric Absorption
Oxygen
Pyloric Antrum
Jejunum
Humidity
Dehydration
Duodenum
Intestines
Healthy Volunteers
Fever
Body Weight

All Science Journal Classification (ASJC) codes

  • Physiology
  • Physiology (medical)

Cite this

Ryan, A. J., Lambert, G. P., Shi, X., Chang, R. T., Summers, R. W., & Gisolfi, C. V. (1998). Effect of hypohydration on gastric emptying and intestinal absorption during exercise. Journal of Applied Physiology, 84(5), 1581-1588.

Effect of hypohydration on gastric emptying and intestinal absorption during exercise. / Ryan, A. J.; Lambert, G. Patrick; Shi, X.; Chang, R. T.; Summers, R. W.; Gisolfi, C. V.

In: Journal of Applied Physiology, Vol. 84, No. 5, 01.05.1998, p. 1581-1588.

Research output: Contribution to journalArticle

Ryan, AJ, Lambert, GP, Shi, X, Chang, RT, Summers, RW & Gisolfi, CV 1998, 'Effect of hypohydration on gastric emptying and intestinal absorption during exercise', Journal of Applied Physiology, vol. 84, no. 5, pp. 1581-1588.
Ryan, A. J. ; Lambert, G. Patrick ; Shi, X. ; Chang, R. T. ; Summers, R. W. ; Gisolfi, C. V. / Effect of hypohydration on gastric emptying and intestinal absorption during exercise. In: Journal of Applied Physiology. 1998 ; Vol. 84, No. 5. pp. 1581-1588.
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abstract = "Dehydration and hyperthermia may impair gastric emptying (GE) during exercise; the effect of these alterations on intestinal water flux (WF) is unknown. Thus the purpose of this study was to determine the effect of hypohydration (~2.7{\%} body weight) on GE and WF of a water placebo (WP) during cycling exercise (85 min, 65{\%} maximal oxygen uptake) in a cool environment (22°C) and to also compare GE and WF of three carbohydrate- electrolyte solutions (CES) while the subjects were hypohydrated. GE and WF were determined simultaneously by a nasogastric tube placed in the gastric antrum and via a multilumen tube that spanned the duodenum and the first 25 cm of jejunum. Hypohydration was attained 12-16 h before experiments by low- intensity exercise in a hot (45°C), humid (relative humidity 50{\%}) environment. Seven healthy subjects (age 26.7 ± 1.7 yr, maximal oxygen uptake 55.9 ± 8.2 ml · kg-1 · min-1) ingested either WP or a 6{\%} (330 mosmol), 8{\%} (400 mosmol), or a 9{\%} (590 mosmol) CES the morning following hypohydration. For comparison, subjects ingested WP after a euhydration protocol. Solutions (~2.0 liters total) were ingested as a large bolus (4.6 ml/kg body wt) 5 min before exercise and as small serial feedings (2.3 ml/kg body wt) every 10 min of exercise. Average GE rates were not different among conditions (P > 0.05). Mean (±SE) values for WF were also similar (P > 0.05) for the euhydration (15.3 ± 1.7 ml · cm-1 · h-1) and hypohydration (18.3 ± 2.6 ml · cm-1 · h-1) experiments. During exercise after hypohydration, water absorption was greater (P < 0.05) with ingestion of WP (18.3 ± 2.6) and the 6{\%} CES (16.5 ± 3.7), compared with the 8{\%} CES (6.9 ± 1.5) and the 9{\%} CES (1.8 ± 1.7). Mean values for final core temperature (38.6 ± 0.1°C), heart rate (152 ± 1 beats/min), and change in plasma volume (-5.7 ± 0.7{\%}) were similar among experimental trials. We conclude that 1) hypohydration to ~3{\%} body weight does not impair GE or fluid absorption during moderate exercise when ingesting WP, and 2) hyperosmolality (>400 mosmol) reduced WF in the proximal intestine.",
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